Following the signing of the deal, widespread protests broke out across Egypt.

Opponents of the agreement said it amounted to selling off Egypt's sovereign powers and that it violated the constitution, which bars the surrender of any territory.

Saturday's decision by the Egypt Supreme Court nullifies the contradictory rulings two other lower courts had given, with the Supreme Administrative Court opposing ceding control of the islands and the Court of Urgent Matters approving the deal.

The Supreme Court ruled the deal was not unconstitutional, adding that approving the deal was down to Egypt's legislative body.